Traditional wireless clock systems known in the market today typically consist of a “master” clock having a wireless transmitter and multiple secondary or “slave” clocks having wireless receivers. The secondary clocks may be installed in many rooms in a school, industrial location, large office building or the like. One reason for using a “master-slave” type system is to permit the master clock to maintain the time at all of the secondary clocks in synchronization with the time at the master clock. To do this, typically, the master clock transmits a periodic time signal, correction signal or the like to the secondary clocks. The secondary clocks receive the signal and display the time, or perform a time correction operation, if necessary.
A disadvantage of such a system is that the size of the system is limited to the distance between the master clock transmitter and the secondary clock receivers. Over a long distance, or in electrically noisy or interfering environments, the secondary clocks may not be able to receive valid time signal data from the master clock.
Another disadvantage of this type of system is that the master clock transmitter normally transmits the time signal over a single radio frequency. Therefore, if there is noise or interference at or near that frequency, it will most likely affect the ability of the secondary clocks to receive accurate time data, unless the transmission frequency is changed manually.
Also, in a system containing multiple secondary or slave clocks, each of which may wirelessly transmit simultaneously, another issue to be addressed is how to prevent the slaves from conflicting with each other. In this context, “conflict” means that a clock receives signals from two or more other clocks simultaneously. The signals may be out of phase. If so, the clock receiving both signals would not “know” which signal to use for accurate timekeeping.
Thus, a need exists for a system and method to prevent signaling and other conflicts at the secondary clocks, particularly in large clock systems operating over long distances or in noisy environments.